This application is submitted in response to RFA DK-07-012 which solicits applications from qualified investigators for the continuation and expansion of the Drug Induced Liver Injury Network (DILIN). Indiana University, one of the founder members and a top recruitment site, has robustly participated in all DILIN operations since its inception. In addition to accelerated subject recruitment, the DILIN during the next funding period will also focus on developing or supporting mechanistic and therapeutic ancillary studies, developing and validating optimal causality instruments and constructing in conjunction with NLM an authoritative hepatotoxicity database. We propose the following specific aims to meet the goals of this RFA. Specific Aim # 1: To enroll large number of eligible adults and children with suspected DILI into ongoing DILIN prospective and retrospective studies. We propose to collect prospective and retrospective cases of suspected DILI from multiple traditional as well as unique sources in Central Indiana, each providing distinctive epidemiological facets and research potential. Specific Aim # 2: To robustly participate in the development and the support of mechanistic (genetic and non-genetic) and therapeutic ancillary studies by investigators within and outside the DILIN. We propose to conduct a network wide therapeutic ancillary pilot study of systemic steroids in patients with well characterized DILI during the next funding period. Specific aim # 3: To continue to participate in a robust fashion in the causality assessment of suspected DILI cases that are enrolled into our ongoing studies and to play a major role in developing and validating new causality instrument(s) that are optimal and user-friendly. Specific aim # 4: To develop, in conjunction with stake holders, an authoritative electronic DILI database, and outreach and educational activities for practicing physicians and the public. Our role will be extensive at conceptual, methodological, operational and contextual levels. Specific aim # 5: The objective is to develop, in conjunction with other DILIN investigators, an international consortium of DILI to facilitate exchange of ideas, standardization of nomenclature, collaborative studies and cross validation of each other's observations and discoveries.